Generally, small hand-operated pumps are used in cosmetic containers that discharge a desired amount of liquid or emulsion contented therein for their convenience. In particular, such hand-operated pumps are widely used since they allow convenient and easy discharge of the contents of a container in uniform aliquots. Technology related to the hand-operated pump has been steadily developed.
A conventional small hand-operated pump includes a housing that constitutes the external appearance of the pump, a closure used to mount the housing in a container, a stem connected to a discharge hole of a button to move vertically along the housing, a shaft for guiding the vertical movement of the stem and for connecting the stem to the button, a piston that which moves vertically along the inner wall of the housing while being mounted in the stem, a spring mounted in the lower portion of the inner wall of the housing, and a ball for opening and closing the receiving hole in the lower end of the housing.
Such a conventional hand-operated pump has some problems.
First, a compression spring that provides restoring force to the stem during pumping is provided inside the housing in the introducing passage channel of contents such that the compression spring serves as a flow resistance factor. Therefore, a highly elastic spring or a large space in the housing is required, which restricts pumping and increases the size of the pump. Also, it is difficult to pump highly viscous contents.
Second, since the compression spring contacts the contents, when the compression spring deteriorates, it is likely that the contents will be contaminated.
Third, since the opening and closing ball in the introducing hole in the lower end of the housing opens and closes the introducing hole due to changes in the pressure of the space inside the housing and the force of gravity, it is not possible to rapidly manage the pumping operation and to provide high sealing force. Therefore, some portion of the contents may leak out of the container during pumping and opening and closing operations are not rapidly performed such that pumping force is deteriorated.
In order to solve such problems, various structures have been developed. However, a hand-operated pump that provides satisfactory results has yet to be produced.